Electroexcitation of rotational vibrations inDy164

We calculate the M1 spectrum and the distorted-wave Born-approximation (e,e’) form factors of the strong ${\mathrm{K}}^{\mathrm{\pi }}$ ${=1\mathrm{}}^{+}$ states in ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$, using a deformed Woods-Saxon potential and the quasiparticle random-phase approximation with quadrupole, spin, and spin-quadrupole interactions. A residual rotation-vibrational coupling ensures the exclusion of the spurious state. We find strongly orbital M1 states at 3.1 MeV which fit the experimental spectrum very well and exhaust 40% of the collectivity of the $1^{+}$ mode. The form factor of the lowest one of these states is also in a good agreement with the experimental form factor.